Pipette washer



J. H. BREWER PIPETTE WASHER April 8, 1947.

Filed May 5, 1.944

Patented Apr. 8, 1947 UNITED STATES PATENT OFFICE PIPETTE WASHERcorporation of Maryland Application May 3, 1944, Serial No. 533,872

2 Claims. (01. 137-20) This invention relates to an apparatus forwashing pipettes and similar devices of tubular shape.

It has been customary heretofore to employ relatively complicated andexpensive apparatus for Washing pipettes.

An object of the present invention is to provide a pipette washer whichis inexpensive and of such a simple construction that it can be made bya skilled chemical laboratory technician, and simple and efficient inoperation.

A further object of my'invention is to provide a pipette washercomprising a siphon device adapted to be applied to or withdrawn from astandard container or vessel for the pipettes to be washed without anypermanent or temporary attachment to the container or associatedinterchangeably with a purality of such containers.

My invention consists of a vessel adapted to contain the pipettes orother articles to be washed and a siphon device adapted to be attachedto a supply of the washing liquid which will peri-' odically fill andempty the container and thus in time repeatedly fill and empty thepipettes and thereby wash them.

The invention is illustrated in the accompany ing drawings in which:

Fig. 1 is a front elevation, partly in section. of the apparatus;

Fig. 2 is a fragmentary elevation with parts shown in sectionillustrating a modification of the apparatus in which the siphon tube isflattened where it passes over the edge of the container;

Fig. 3 is a fragmentary elevation with parts in section showing theobstruction of the filling tube by pinching it and;

Fig. 4 is a fragmentary elevation partly in section showing theobstruction of the filling tube by introducing an obstruction.

Referring to the drawing, l is the container which may be an ordinarygraduate such as generally is available in laboratories and other placeswhere pipettes are to be washed. In the specific embodiment illustratedin Fig 1, the container l is a 1000 cc. graduate but it will beunderstood that any other suitable vessel of sufficient depth tosubmerge the pipettes and hold them in substantially vertical positionmay be used. One might, for instance, use a tank of relatively largecross section with means such as a rack therein for holding the pipettesin vertical position, but it will be appreciated that in order to savewashing liquid it is preferable to use a container which is only largeenough to hold the number of pipettes to be washed. 2,2 are the pipettesto be washed. The siphon device consists of the filling tube 3 adaptedto extend substantially to the bottom of the container I, connected tothe rubber hose 4 adapted to be attached to a water faucet or othersource of washing liquid and the siphon tube 5 connected to the fillingtube 3 through the opening 6.

The siphon tube 5 bends up over the edge of the container 1 and thendownwardly preferably to or below the level of the bottom of thecontainer I. In the embodiment illustrated tubes 3 and 5 are made ofcopper but may be made of any other suitable material such as glass orsynthetic resin or plastic. The bend l of tube 5 is adapted simply torest on the edge of container 1 and may therefore be appliedinterchangeably to other containers of substantially equal depth.

In operation, the pipettes 2, 2 to be washed are placed in the containerl, tube 3 is inserted so that the bend l of tube 5 rests on the edge ofthe container, rubber hose 4 is connected to a water faucet and thewater turned on at a rate of fiow which is less than (preferably abouthalf) that at which the siphon is capable of emptying the container. Thewater from the faucet fiows through hose 4 and tube 3 and graduallyfills the container I and pipettes 2, 2 which do not, of course, make aliquid tight seal with the bottom of the container I. If it were foundthat the pipettes did make a liquid tight seal with the bottom of thecontainer, this difliculty could be met by e. g. dropping a disc of wiregauze into the bottom of the container 1 to provide a grill forsupporting the pipettes so that the wash water would fiow into and outof them freely.

When the liquid level in container l nears the top edge thereof, theliquid level in that portion of tube 5 within the container I will, ofcourse, rise by gravity to the same level and the slight pressure in thetube 3 created by the fiow .of water from the faucet is sufficient toforce the water through the bend 1 thereof and start the operation ofthe siphon. The siphon then functions to withdraw water from thecontainer through tubes 3 and 5 and since the flow of water through thesiphon is greater than the flow through hose 4, the container will beemptied. At this point the water column in the siphon breaks and thefiow through the siphon stops and the container l is then refilled bythecontinuing flow of water from the source, this cycle being repeatedcontinuously so that in the course of a few hours, say over night, thepipettes will be filled and emptied a number of times.

In order to facilitate the priming of the oper- 3 ation of the siphon itis desirable to flatten the tube 5 at the bend as shown at I in Fig. 2to reduce as much as possible the height that the washing liquid must beraised in the tube 5 above the level of the liquid in the container l.Another expedient which favors priming of the siphon is to restrict theflow of water through the tube 3 as compared with the flow from tube 3through the opening 6 into tube 5. This may be done by pinching arestriction 8 in the tube 3 as shown in Fig. 3 or by introducing anobstruction 9 into the tube 3 below the opening 6 as shown in Fig. 4 sothat as the water flows from the faucet through hose 4 and tube 3 intothe container, a slight back pressure through opening 6 into tube 5 willbe created sufficient to cause it to overflow the point I when the levelof the liquid in the container l approaches the upper edge thereof.

As will be apparent, the siphon device 3-4"'5-6-'-7 may be applied toand Withdrawn from the container I without handlinr "be clean pipettes.The container i may be lvdded with soiled pipettes and the siphon devicethen applied to wash the pipettes and then withdrawn leaving the cleanpipettes in the container until they are needed. The siphon may then bereturned to the same container to wash another batch of dirty pipettesor it may be transferred to another container or to a plurality ofcontainers in sequence loaded with pipettes to be washed. Thus itbecomes unnecessary to provide a plurality of pipette washers or toremove clean pipettes from the washer and store them elsewhere understerile conditions While another batch of dirty pipettes is beingwashed. In effect my invention makes a pipette washer and clean pipettestorage container of every one of tljie available containers in alaboratory.

I. A washer comprising a siphon device having a. main tube adapted to beconnected at one end to a source of washing liquid and to be positionedwith its other end extending downwardly into a container and a branchtube connected to said main tube intermediate the ends thereof, saidbranch tube being adapted to extend over the edge of the container anddownwardly outside the container when said main tube is positionedwithin said container, the opening through the main tube beingrestricted at a point between its connection to the branch tube and saidother end thereof to a size which is smaller than the passageway throughsaid branch tube including its connection to said main tube.

2. The combination with a vessel having a free upper edge and a sourceof supply of liquid, of a siphon device consisting of a main tube extending downwardly into said vessel and upwardly above the lowermost pointof said edge and attached to said source of liquid, an opening in theside wall of said main tube below the level of the lowermost point ofsaid edge and a second tube having an end connected to said opening anda portion extending upwardly over the lowermost point of said edge andsubstantially in contact therewith and another portion extendingdownwardly outside of said vessel, said source of liquid beingadjustable to a rate suificient to elevate the liquid in said secondtube over the lowermost point of said edge to initiate syphonic action.

JOHN H. BREWER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,319,531 Brown et a1. May 18,19% 1,088,973 Drinkhouse Mar. 3, 1914 1,731,899 Huntworth Oct. 15, 19292,345,284 Myers et a1 Mar. 28, 1944

